Grinding machine



May 7, 1940. F. A JONES 2,200,025

GRINDING MACHINE Filed Dec. 15, 1937 2 Sheets-Sheet I.

g gg y dllouuu y 0: F. A. was 2,200,025

GRINDING MACHINE Filed Dec. 15, 1937 2 Sheets-Sheet 2 gwwwp Fraizif flJbnes Gum/M Patented May 7, 1940 WENT other I GRINDING MACHINE -Franl-1A. Jones, Greer, S. 0., assignor of onehalf to'R. G. Hcdgson, Greer, S.C.

Application December. 15, 1937, Serial No. 179,988

11 Claims. (01. 51-430) Myfinvention relates to a grinding machine forgrinding the'end of rocker arm'co'mmonly employed for operatingvalves'in internal combustion engines.

An objeotof my invention is to devisea ma chine for grinding the end of-a rocker arm so that the arm will have rolling contact with the end ofthe valve stem, thereby avoiding sliding of the arm over the end of thevalve stem and in. reducing the consequenttwear and friction. By

my invention, the end of therocker arm is provided with cam-like surfacewhich maintains rolling contact. with the end of the valve stem andcauses substantially straight line movement in. of the valve stem,thereby greatly eliminating lateralthrust on the side of the valve stemand preventing excessive Wear between the valve stem and the wall of thevalve stem bushing;

While my invention is designed especially for grindingthe e-ndof arockerarm, it will be obvious that it may be used for grinding otherdevices than'rocker arms. I

A further object is to" devise a work support for a grindingv machinefor grinding a curved: .sn rfaoe fon the work of. relatively largeradius. andrwhereinthe work isTotated'zabouta shifting.

instantaneous center of rotationwhich may be relatively close. to thegrinding surface.

Two modifications of. my invention are il1ustrated in the accompanying.drawings in whichz' Figure 1 is a plan view of one arrangement of thework-supporting carriage forming my grinding machine;

Figure 2 is a side view of. Figure .1; i v

Figure 3 is an end .view of Figure 1; showing. the work supportingcarriage in elevation;

Figures 4, 5 and 6 are kinematic linkage diagrams illustrating theoperation of the arrangement shown in Figures 1 to 3;

Figure 7- shows a rocker arm in operative relation .to a valvestem;

Figure 8 is a fragmentary view'showing a modified formfof the invention;and

Figure 9 is a side view of Figure 3.

wheel. 2

Referring to the drawings, the worlr'supportgrinding face of wheel 2, asshown in Figure 1. A lever ii is pivotaily secured by'a pin 4a to thelever 3 near the outer end thereof and is provided with a slottedextension 4b at the free end and arranged at right angles to its mainaxis and extending over the base I. A stud or pin 5 has a base 5asecured thereto which in turn is adjustably mounted upon lever l as by'means of a pair of screws 5b passing through a slot in the base 5a andhaving threaded engagement with the lever 4. A pair of collars 5c and 5dhavingopposed conical ends are mounted on pin for supporting av rockerarm ti (indicated in dotted lines). It Will be understood that collars5c and 5d areadjustably secured onto pin 5 by suitable 'r'neans such asset screws. Apair of pins to and 4d are mounted upon lever 4 andarranged to embrace opposite sides ofthe front end of the rocker arm asshownin Figure 1 and hold the rocker arm in position against the radialface of .wheeiZ during grinding operation. Pin id is a resilient pin tohold the rocker arm against pin to but permit the rocker arm to moveback in case of too severe contact with the grinding wheell A screw icforming an adjustable stop limits the movement: of base I towardsMounted upon the base i is a bracket 1 having a longitudinal slot laformed therein; the bracket 1 being arranged in line with the angleexten sion ib on lever 4 or at right angles to the grinding surface. Alink 8 is pivotally secured to'extension 4b on lever 4 by means of a pin8a adjustably secured in the slot of the extension 46-; and' 'link 8 isalso pivotally secured to the bracket "4" by'xneans of a pin lbadjustably secured in the slot la by means of a collar To and a nut 103.Link 8 is provided with a' series of holes 8b formed therein to vary theposition of pivotal connection on the link.

As shown'in Figure 1, the parts are in their" normal position and therocker arm 6 is supported on the pin 5 so the face of'the front end to.or the arm is. brought into contact with one radial face of the grindingwheel 2. By swinging thelever 3 by its handle 3a in the directionindicated by arrow A, the lever 3 pivots about the. axis of pin 3b,While the left endof lever 4 is carried with lever 3 due to the pivotalconnection of pin 4a. The right end of lever 4' is guided in" itsmovement by link 8 which is pivotally connected by pin 1b to bracket 1and also has; pivotal connection at 8a tothe extension 4bon lever; 4.The arrangement is such that as the lever 3 is moved in the direction-A,the

end So of the rocker arm is rotated about an axis somewhere near theaxis of pin 31) and at the same time is drawn away from the face of thegrinding wheel 2. It will be clear that upon rotating the handle 3 inthe direction of the arrow B, a similar movement of the end of therocker arm will take place.

. fixed pivot point for lever 3, 411 indicates the pivot point for oneend of lever t on lever 3, and 7b indicates the fixed pivot point forone end of link 8. The line 5 extending from line 4 represents therocker arm which is secured to and carried by lever 4.

Figure 4 represents the linkage arrangement in its normal position, andthe point 622 indicates the point of contact between the rocker arm andthe grinding wheel 2. Since the right end of line 5 tends to rotateabout fixed pivot lb, and the left end of line 4 tends to rotate aboutfixed pivot 3b, the instantaneous center of rotation of the lever 4 isrepresented by the point 3?) where the center line of link 8 intersectsthe center line of lever 3.

Figure 5 represents the arrangement where the lever 3 has been movedupward from its normal position. In this condition it will be seen thatthe original point of contact 6b has moved away from the face of thegrinding wheel, and the instantaneous center of rotation of the lever 4has shifted to the right and is located at the point 4e.

Figure 6 represents the arrangement where the lever 3 has been moveddownwardly from its normal position, and under this condition it-will beseen that the original point of contact 61) has also moved away from theface of grinding wheel 2, and the instantaneous center of rotation ofthe lever 4 has shifted to the left and is, located at the point M. j

Upon an inspection of Figures 4, 5 and 6, it will be seen that theinstantaneous center of rotation of the rocker arm shifts substantiallyparallel to the face of the grinding wheel, and while the center ofrotation of the rocker arm is located very close to the face of thegrinding wheel 2, nevertheless, due to the shifting of the instantaneouscenter of rotation, the curvature which is ground on the face of therocker arm has an effective radius very much greater than the distancefrom the instantaneous center of rotation to the face of the wheel. Itwill thus be seen that my invention provides an arrangement by which acurvature of relatively large effective radius may be ground upon alimited surface without interference between other parts. of the Workand the grinding wheel. The desired curvature cannot be ground by usinga fixed center of rotation nor by using a great radius of rotationbecause the edge of the wheel would cut into the web of the rocker arm.

In Figure '7 I have shown a rocker arm in operative relation with theupper end of a valve stem 9. vIn position 3A, the rocker arm is shown inits up iermost position, while at 6B the arm is shown in itsmid-position, and at BC the arm is shown in its lowermost position. Inorder to produce rolling contact between the face of the rocker arm andthe upper surface of the valve stem, it is desirable that the point ofcontact progress sub-' 4 stantially uniformly from a point onthe edgeofthe valve stem nearest the center of oscillation of the rocker arm to apoint on the opposite side of the valve stem. The line to represents thepath of travel of the point of contact between the rocker arm and theupper end of the valve stemf and it will be seen that the contact shiftsfrom left to right as the rocker arm is moved from its upper position toits lowermost position. Stated another way, the point of contact shiftsto the left when the valve is raised from its mid-position and shifts tothe right when the valve is depressed commodated by adjusting theposition of the.

supporting pin 5 along the length of lever 4. The

position of the fixed p-ivot'lb for the link 8 may be adjusted byshifting the pivot in the slot Ia formed in bracket I, and the length ofthe link 8 may be adjusted by shifting the connection to different holes8b formed in the link, and alsoby shifting the pivot 3a in the slotformed in extension 4b. It will be understood that instead of using aseries of separate holes 8b in link- 8, an elongated slot may be formedin this link.

In Figures 8 and 9 I have shown a modified arrangement for guidingthe'right-hand end of the lever 4. In this arrangement the lever 3 ispivots ed to the base I on pin3b asin Figure 1, and the lever 4 islikewise pivoted to the lever 3 in the same manner as in Figure 1, butnot shown'in Figure 8 due to the fragmentary showing of thesev twolevers. A gear Wheel I0 is securely mounted upon the pin 32) which isjournaled in-base I and turns with the lever 3, whereby the gear wheelI0 rotates with the lever 3. A second gear wheel I I is mounted upon ashaft I la which is journaled in base plate I and extends through to the0pposite side of the plate, gear II is arranged to mesh with gear Iflandis driven by gear Ill. The opposite end of the gear shaft I la has akey-like connection with the slot in a lever I2 which isadjustablysecured to the end of shaft IIaby a nut I Iband rotates with gear II., Alink I3 joints the lever I2 to the free end of lever 4 by means of pivotI2a carried by the arm I2 and the pivot I3a joining the other end oflink I3 to lever 4. The pivot 12a is adjustable in theslot I3b in linkI3. It will be understood that lever 4 carries pins like 5, 4c and 4d ofFigure 1 for supporting a rocker arm.

The arrangement shown in Figures 3 operate generally in the same manneras the and 9 will' arrangement shown in Figures 1 to 3, in that movementof the arm 3 from its normal position in either direction will cause arotation of the arm I2 from its normal position, and, through the actionof link I3 will move the free end of the lever 4 away from the face ofthe grinding wheel. In other words, the arrangement is such that therocker arm carried by the lever 4 will rotate about aninstantaneouscenter which shifts along: a path substantially parallel with thegrindingface of the grinding wheel While my invention has-been shown anddescribed: as particularly suited for grinding the working surface on arocker arm, it will be understood that it maybe used for grinding otherarticlesif desired. Variousmodifications will be obvious-to thoseskilled in the art, andrny invention is restricted only. in accordancewith the terms .of itheappended claims. l

What I. claimis: 1. In combination, a grinding. element having afiatgrinding surface, a work carriage comprisingv asupporting base arrangedfor sliding movement inv a-direction. substantially at rightanglestorsaidwgrinding surface, a lever pivoted to said sliding base andnormally extending substantially parallel to said grinding surface, butbeing swingableuto. either side of saidnormal position, a link pivotedto said sliding base and normally arranged at right angles to said leverand extending. towards the pivotal axis of. said lever, a second leverpivotally supported atone end upon the first lever at a point removedfrom its. pivotal axis, means for guiding the free end of said second'lever in a. curved pathcomprising a connection: between the free end ofsaid second lever and said link at a point thereon removed from itspivotal axis, and means carried by said second lever. for supporting awork-piece in contact with .said grinding surface.

, lever at a point removed from. its pivotal axis, said second leverbeing normally arranged so the free end thereof lies adjacent the pivotpoint of the first lever, a lateral extension on the free end of saidsecond lever arranged in line with said link and having a longitudinalslot formed therein, adjustable pivot means mounted in said slot forpivotally connecting the free end of the second lever to the free end ofsaid link, and means carried by said second lever for supporting aworkpiece in contact with said grinding surface.

3. In combination, a grinding element having a fiat grinding surface, awork carriage comprising a supporting base arranged for sliding movementin a direction substantially at right angles to said grinding surface, alever pivoted to said sliding base, a gear secured to said lever andarranged to rotate about the pivotal axis thereof, a second leverpivoted to said sliding base, a gear secured to said second lever andarranged to rotate about the pivotal axis thereof, said second gearhaving meshing engagement with the first gear whereby the second leveris driven by the first lever, a third lever pivotally secured at one endto said first lever, a link element pivotally secured at one end to saidsecond lever and having its free end pivotally connected to'the free endof the third lever, and means carried by said third lever for supportinga work-piece in contact with said grinding surface.

4. A work support for a grinding machine compivoted tosaid base, a gearsecured to said second lever and arranged to rotate about the pivotalaxisthereof, said second gear having meshing engagement withthe firstgear whereby the second lever is driven by the first lever, a thirdlever pivotally secured at one end to said first lever, a

link element pivotally secured at one end to said second lever andhaving its free end pivotally connected to the free end of the thirdlever, and

meanscarried by said third lever for supporting a. work piece.

5. In a machinefor grinding rocker arms, the combination of a grindingelement having-a flat grinding surface, a work carriage comprising asupporting base, a lever pivoted to said base on an axis parallel withsaid grinding surface, said lever normally extending substantiallyparallel to said grinding surface but being swingable to either side ofsaid normal position, a link pivoted toasaid base and normally arranged.at right angles to said lever. and extending towards the prising incombination-a work carriage comprispivotal axis of the lever, thepivotal axes of said lever and said link being located in a plane sub-"stantially at right angles to said grinding surface,

a second lever pivotally supported at one. end:

uponthe first lever at a point removed from its pivotal axis, aconnection between the free end of said second lever and said link atapoint thereon removed from its pivotal axis, a pin supported upon saidsecond lever at a point removed from the pivotal points thereof, andmeans for sup porting a rocker arm on said pin with the face of therocker arm in position to engage said grinding surface.

6. In combination, a grinding element having a fiat grinding surface, awork carriage comprising a supporting base, a lever pivoted to said baseand normally extending substantially parallel to said grinding surface,a link pivoted to said base and normally arranged at right angles tosaid lever and extending towards the pivotal axis of said lever, asecond lever pivotally supported at one end upon the first lever at apoint removed from its pivotal axis, said second lever being normallyarranged so the free end thereof lies adjacent the pivot point of thefirst lever, a lateral extension 'on the free end of said second leverarranged in line with said link and having a longitudinal slot formedtherein, adjustable pivot means mounted in said slot for pivotallyconnecting the free end of the second lever to the free end of saidlink, and means carried by said second lever for supporting a work-piecein contact With said grinding surface.

7. In combination, a grinding element having a fiat grinding surface, awork supporting base, a lever pivoted to said base on an axis parallelto said grinding surface and located near the plane of said grindingsurface, a second lever pivoted to said base on an axis parallel to thepivotal axis of the first lever and arranged at right angles to saidgrinding surface with respect the pivotal points thereof and in apositionto engage said grinding surface.

, 8. In combination, a grinding element having a fiat grinding surface,a work carriage comprising a supporting base arranged for slidingmovement in a direction at substantially right angles to said grindingsurface, a lever pivoted to said sliding base on an axis parallel tosaid grinding surface, said lever being normally arranged substantiallyparallel to said grinding surface but being swingable to either side ofsaid normal positin, a second lever pivoted at one end to said firstlever at a point removed from its pivotal axis, means carried by thesecond lever for supporting a work-piece in contact with the grindingsurface, and means for guiding the free end of said second lever wherebythe work-piece is drawn away from the grinding surface when said firstlever is moved in either direction from said normal position.

9. A work support for a grinding machine comprising in combination, abase, a lever pivoted to said base, said lever having a normal positionbut being swingable to either side of said position, a second leverpivotally supported at one end to said first lever at a point removedfrom the pivotal axis of the first lever, the free end of said secondlever normally extending back towards the pivotal axis of the firstlever, a link element pivotally secured to said base at a pointsubstantially at right angles to the first lever from its pivotal axis,and a pivotal connection between the free end of said link and the freeend of said second lever, and means carried by said second lever forsupporting a work-piece.

10. In combination, a grinding element having a fiat grinding surface, awork carriage comprising a supporting base, a lever pivoted to said baseand normally extending substantially parallel to said grinding surface,but being swingable to either side of said normal position, a linkpivguiding the free end of said second lever in a curved path comprisinga connection between the free end of said second lever and said link ata point thereon removed from its pivotal axis, and

means carried by said second lever for supporting.

a work-piece in contact with said grinding sur-' face.

11. In cdmbination, a grinding element having a flat grinding surface, awork carriage comprising a supporting base, a lever pivoted to said baseon an axis parallel to said grinding surface, said lever being normallyarranged substantially parallel to said grinding surface but beingswingable to either side of said normal position, a second lever pivotedat one end to said first lever at a point removed from its pivotal axis,means carried by the second lever for supporting a workpiece in contactwith the grinding surface, and

means for guiding the free end of said second lever whereby thework-piece is drawn away from the grinding surface when said first leveris moved in either direction from said normal position.

FRANK A. JONES.

